1. Field
Aspects of the present invention relate to a method of manufacturing an organic light emitting diode display. More particularly, aspects of the present invention relate to a method of manufacturing an organic light emitting diode display that can display an image by light emission of an organic material.
2. Description of the Related Art
An organic light emitting diode display is a self emissive display that displays an image using an organic light emitting diode to emit light.
Thin film transistors (TFTs) and capacitors used in the organic light emitting diode display include a polysilicon film depending on the types of TFTs and capacitors. The polysilicon film is formed by polycrystallizing an amorphous silicon film. The amorphous silicon film can be polycrystallized by various known methods.
Among polycrystallization methods, an excimer laser annealing (ELA) method is widely used because this method enables polycrystallization at a relatively low temperature, and allows the formation of a polysilicon film with excellent characteristics including relatively high electron mobility. In the excimer laser annealing (ELA) method, an amorphous silicon film is polycrystallized by scanning and irradiating an excimer laser beam having the shape of a line.
However, as organic light emitting diode displays are becoming larger in size, the polysilicon film is becoming larger in area. It is difficult to form such a polysilicon film having a large area by performing scanning and irradiation only once. Thus, a polysilicon film is usually formed by scanning and irradiating the excimer laser beam onto an amorphous silicon film twice or more.
However, if the excimer laser beam is scanned and irradiated onto the amorphous silicon film twice or more, some regions are irradiated with the excimer laser beam twice due to process tolerance. That is, the polysilicon film is divided into a region irradiated once with the excimer laser beam and a region irradiated twice with the excimer laser beam. There is a difference in crystallinity between the region irradiated once and the region irradiated twice, such that the regions have different characteristics. Therefore, the characteristics of such elements as a thin film transistor of the organic light emitting diode display become non-uniform.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.